McCune Albright syndrome (MAS) is rare with a prevalence of 1 in 100,000 to 1 in 1,000,000, characterized by the triad of monostotic/polyostotic fibrous dysplasia (FD), café au lait skin pigmentation, and hyperfunctioning endocrinopathies caused by somatic activating mutations of the GNAS1 gene encoding the α subunit of guanine nucleotide-binding protein. Here we are reporting three cases of MAS who are actively being followed up in a leading Children’s Hospital in Sri Lanka.
Patient 1: 3 year old boy presented with bilateral frontal prominence, multiple café au lait spots, large hands and feet with height >97th centile, right leg deformity and pubertal genitalia. Investigations revealed increased testosterone with undetectable gonadotrophins, increased Prolactin and growth hormone. He had hypophosphatemic rickets and features of fibrous dysplasia in the skull. He was started on spironolactone, cabergoline, Phosphate buffer, 1 alpha calcidol with regular intravenous bisphosphonate. He continued to have high IGF-1 and GH level needing long acting octreotide at 11 years. He’s now 17 years and 2 months and his serum cortisol and thyroid function remained normal throughout with no effect on hearing and vision.
Patient 3: 2 year old girl presented with a history of low impact R/femur fracture, multiple café-au-lait spots and thyrotoxicosis and commenced on regular intravenous Bisphosphonate, anti-thyroid drugs and beta blockers. She is on phosphate buffer and 1 alpha calcidol for hypophosphataemic rickets. She underwent thyroidectomy at 4 years due to uncontrolled thyrotoxicosis and she’s currently on Thyroxine replacement. At 2years and 9 months, she developed vaginal bleeding, diagnosis of GIPP was made and started on oral Letrazole. Other endocrine functions are normal at 5 years. MAS has various different presentations therefore it’s important to follow them up regularly and actively look for developing endocrinopathies.
15 Sep 2022 - 17 Sep 2022